This invention relates to an information recording/playback apparatus and, more particularly, to an information recording/playback apparatus for recording and reproducing still-picture information that has been received.
A high-definition television signal (hereinafter referred to as a HDTV signal) has a large number of scanning lines and presents a very fine image. For these reasons, it is expected that such a signal will find use in the transmission of still pictures, e.g., the transmission of works of art such as paintings, animations, still pictures for medical purposes, for merchandise catalogues and the like.
In a case where a still picture is transmitted as a broadcast wave, as described above, it has been contemplated to compress the picture to a degree that will not diminish picture quality, and to annex thereto a synchronizing signal and an error-check code (hereinafter abbreviated to ECC). Though various media are usable for storing the still picture on the receiving side, a disk-shaped recording medium generally is suitable in terms of its random-access capability, cost and recording capacity.
FIG. 2 is a diagram illustrating the construction of a system for a case where it is assumed that a still-picture signal transmitted as set forth above is received and recorded on a disk-shaped recording medium, with use being made of an ordinary technique. As shown in FIG. 2, numeral 1 denotes a tuner which receives a still-picture information code that has been transmitted as a broadcast wave, and which extracts the code as an electric signal. An ECC decoding circuit 2 is for decoding the ECC annexed to the still-picture code extracted by the tuner 1, and for performing error correction. A buffer 4 transmits the corrected still-picture code to a bus A functioning as an address/data bus.
A microprocessing unit (MPU) 40 carries out an exchange of information data and address data with each of various devices via the bus A. The still-picture data transmitted to the bus A via the buffer 4 is read into the MPU 40, in which the data is put into the form of a code suitable for recorded data, after which the code is accepted by a disk recording circuit 21 via the bus A.
The disk recording circuit 21 subjects the still-picture code processed by the MPU 40 to such processing as modulation necessary for recording, and supplies its output to a disk device 22. The latter records the still-picture signal on the disk-like recording medium.
The still-picture signal reproduced from the disk-shaped recording medium inside the disk device 22 is converted into a code by a disk playback circuit 23. The code is supplied via the extended bus A to the MPU 40, where the code is returned to the form of the original code. The MPU 40 supplies the still-picture information code, which as been returned to the originally coded form, to the buffer 13 via the bus A. This still-picture information code is outputted from an output terminal 17 via the buffer 13, thereby to be supplied to a monitor unit or the like having an internal decoder for decoding the compressed code.
In the system described above, various codes necessary for a transmission in the form of broadcast waves are annexed to the still-picture information code data. Accordingly, in a case where such transmission code data is recorded on a disk-shaped recording medium, the recording medium is required to have a large capacity even if a small number of still pictures are recorded.